Objective: To analyze the clinical effect of folic acid, dydrogesterone tablets combined with magnesium sulfate in the treatment of gestational hypertension. Methods: A total of 86 patients with gestational hypertension in our hospital from January 2023 to January 2025 were selected and randomly divided into the conventional group (43 cases, treated with magnesium sulfate) and the study group (43 cases, treated with folic acid and dydrogesterone tablets on the basis of the conventional group). The clinical effects, blood pressure levels, Th1 cell levels, Th2 cell levels, oxidative stress levels [malondialdehyde (MDA), ischemia-modified albumin (IMA), myeloperoxidase (MPO)] and vascular endothelial functions [nitric oxide (NO), endothelin-1 (ET-1)] of the two groups were compared. Results: The total effective rate was 93.02% in the study group and 76.74% in the conventional group (P < 0.05). Compared with the conventional group after one week of treatment, the levels of SBP and DBP in the study group were significantly decreased (P < 0.05). Compared with the conventional group after one week of treatment, the Th1 level in the study group was significantly decreased and the Th2 level was significantly increased (P < 0.05). Compared with the conventional group after one week of treatment, the levels of MDA, IMA and MPO in the study group were significantly decreased (P < 0.05). Compared with the conventional group after one week of treatment, NO in the study group was significantly increased and ET-1 was significantly decreased (P < 0.05). Conclusion: Folic acid, dydrogesterone tablets combined with magnesium sulfate have a definite effect in the treatment of gestational hypertension. They can improve the immune and oxidative stress levels of the body, improve vascular endothelial function, and significantly lower blood pressure levels.